Bulk single crystals of ammonium acid phthalate grown by the Sankaranarayanan-Ramasamy method for optical limiting applications

Transparent ammonium acid phthalate (AAP) crystal of length 55 mm and diameter 18 mm has been grown from aqueous solution along <001> using the Sankaranarayanan-Ramasamy method. The unit cell parameters were confirmed by single crystal X-ray diffraction analysis and it belongs to orthorhombic system. The crystalline perfection of grown crystals was analyzed by high-resolution X-ray diffraction. The UV-vis-NIR spectrum showed that the grown crystal is transparent in the entire visible region. Nonlinear optical absorption of the sample has been studied at 532 nm using single 7 ns laser pulses, employing the open-aperture Z-scan technique. It is found that the AAP crystal is a potential candidate for optical limiting applications. The laser damage threshold was measured using Q-switched Nd:YAG laser (1064 nm).